Feedstuffs are used to feed and raise livestock. Such livestock can be harvested for its meat. Alternatively, livestock can be the source of produce such as eggs and milk, which may be consumed as milk, or converted into another dairy product, such as cheese or yogurt. To produce healthy livestock and increase the yield of produce, it is important for their feed to contain sufficient protein.
Recently, the production of ethanol from corn has become commercially important. In the dry milling (mash distillation) production of ethanol from corn, the process begins by grinding corn into a coarse flour. After the flour is combined with water and/or enzymes to convert the starch to sugar, the product is sterilized and then cooled. After yeast fermentation, ethanol is distilled from the mash. The residual mash is sent to either a centrifuge or screen press to remove as much liquid as possible. The liquid, referred to as corn distillers solubles may be returned to process or sold as a feed additive. The wet distillers grains may also be sold as livestock feed or dried to afford dried distillers grains (DDG).
The DDG is a good source of protein, and it would be desirable to use the DDG as a component of a diet for livestock. However, to make efficient use of DDG in the production of a feed for livestock, the DDG must be dried. Such drying can lead to heat damage of the protein which can, in turn, lead to decreased digestibility of the protein, decreased growth of the livestock, and/or decreased milk production (Non-patent Citation 1 and 2).
Trimethylglycine (also commonly known as TMG or betaine) is an organic compound of the formula (CH3)3N+CH2CO2H. Trimethylglycine was originally named betaine after its discovery in sugar beets (Beta vulgaris) in the 19th century. Betaine occurs widely in nature and its principal physiologic roles have been described as an osmolyte and a methyl donor (Non-patent Citation 3). Betaine is also included in a product which is commercially available as PROTEFERM®. PROTEFERM® is a condensed, extracted glutamic acid fermentation product, and a liquid feed byproduct from the manufacture of monosodium glutamate (MSG).
Patent Citation 1, 2, and 3 disclose a ruminant feed supplement prepared by drying a mixture of glutamic acid fermentation solubles and corn fermentation solubles on a wheat middlings carrier. Patent Citation 4 discloses soil adjuvants prepared in the same way. Corn fermentation solubles are a liquid byproduct of the manufacture of amino acids using corn sugar as a raw material and include very small amounts of protein. Wheat middlings are low in crude protein (17.4 wt. % protein on dry matter basis (Non-patent Citation 4) and not considered a protein-rich feedstuff. Thus, these references do not contain any disclosure of stabilizing the proteins in a protein-rich material during drying.
In addition, PROTEFERM® has been used as an additive to pelletize dried distillers grains with solubles. When added at levels equal to between 5 and 10% on a weight by weight (w/w) basis of dried distillers grains, PROTEFERM® has been able to improve pellet durability and hardness compared with no additive material. The addition of PROTEFERM® to dried distillers grains to equal 10% of the weight is roughly equivalent to adding 1.8 grams of betaine per 100 grams of protein contributed by distillers grains. (This equivalent value can be calculated with the understanding that the betaine content of PROTEFERM® is about 5% and that the crude protein content of dried distillers grains is about 28%. Thus, for example, when PROTEFERM® is present in an amount of 10 wt. % based on dried distillers grains, the equivalent value of betaine is given by [(5% betaine×9.1)/(28% crude protein×90.9)]×100=1.8.). This level of betaine addition is not an effective level to protect protein from heat damage.